Credit

Caption

Cucumber stem tissue. Light micrograph of a cross- section through the stem of a cucumber (Cucurbita sp.) showing a close up of the sieve cells (blue, two at centre left, one at lower right) in the phloem. It is the holes in the sieve cells that allow cytoplasmic continuity between adjacent sieve cells. Cytoplasm is the fluid contents of a cell, normally retained inside a cell, but here moving between cells through the holes in the sieve cells. The phloem passes nutrients around a plant.